feat(rbac)!: add Azure RBAC engine, FFI API, and cross-language tests (#577)

- add Azure RBAC condition interpreter and builtin evaluation in core (expressions, parser updates, evaluator, and test harness)
- introduce comprehensive RBAC YAML test suites and coverage for i
  - action/suboperation
  - strings
  - numbers
  - bools
  - IP
  - GUID
  - dates
  - times
  - lists
  - quantifiers (ForAnyOfAnyValues, ForAllOfAllValues)
- expose RBAC evaluation through FFI with an `rbac` feature flag enabled by default
- add C# `RbacEngine` wrapper + P/Invoke entrypoint and document usage in C# README
- expand C# tests to execute all RBAC YAML cases with per-case logging
- wire test assets into C# test output and centralize YAML dependency versions

Signed-off-by: Anand Krishnamoorthi <anakrish@microsoft.com>

bindings/csharp/Regorus/NativeMethods.cs

@@ -492,6 +492,16 @@ namespace Regorus.Internal
 
         #endregion
 
+        #region RBAC Methods
+
+        /// <summary>
+        /// Evaluate an Azure RBAC condition expression against a JSON evaluation context.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_rbac_engine_eval_condition", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusResult regorus_rbac_engine_eval_condition(byte* condition, byte* context_json);
+
+        #endregion
+
         #region Target Registry Methods
 
         /// <summary>